After 15 seasons in Cincinnati that have made him the longest-tenured head coach in franchise history, Marvin Lewis is planning to leave the Bengals after this season to pursue opportunities elsewhere, league sources told ESPN.

As he has done in the past, Lewis willingly opted to enter 2017 on the final year of his contract, but unlike other years, this time he is planning to leave Cincinnati, sources said.

With a flurry of head-coaching openings expected in the coming weeks and a shortage of obvious head-coaching candidates with experience, Lewis is likely to be on teams' short lists of candidates, league sources said.

If a head-coaching job does not materialize, sources said Lewis would be interested in working in another team's front office or as a coaching adviser for a former Bengals assistant coach who has gone on to become a head coach, such as Mike Zimmer, whose Minnesota Vikings host the Bengals on Sunday.

Not only is Lewis' contract up, but so are those of most, if not all, of the Bengals' assistant coaches. The Bengals have declined to give contract extensions to their assistant coaches, and some are unhappy with the way they have been treated financially, sources said.